Both units at Fortum’s Loviisa NPP in Finland are back online after completion of their annual outages. Unit 2 underwent a short 23-day annual outage that ended on 27 August. The extensive four-yearly outage of unit 1 lasted 39 days and ended on 9 October.
Unit 2’s outage was delayed by 2.5 days after a fault requiring repair was detected during inspections on the secondary circuit and additional time was needed for valve testing. The annual outage of unit 1 was initially extended by five days because of delays in pre-planned inspection and maintenance work and repairs to the diesel generator. A further four-day delay occurred when a technical fault was detected in one of the control rods during tests carried out during plant start-up.
“The ramp-up of the plant was suspended in order to determine the cause of the fault and take the necessary corrective measures. The fault was quickly located and the mechanism of the control rod in question was replaced in its entirety. After this, we were able to start up the plant and carry out the necessary tests again,” said Sasu Valkamo, Loviisa NPP Senior Vice President.
“Safety is our guiding star also in annual outage. Annual outages can sometimes uncover maintenance needs or defects that weren’t anticipated, potentially delaying their completion,” he noted. “The equipment and systems are carefully inspected before the plant unit is returned to the network after annual outage.”
The Loviisa plant comprises two Soviet-designed VVER-440 reactors and currently provides more than 10% of Finland’s electricity. Loviisa unit 1 began commercial operation in 1977 and unit 2 in 1981. The plant has been using fuel supplied by Russia’s TVEL since 2007. However, European Union policy is currently focused on diversifying away from Russian supplied fuel. The first batch of Westinghouse Electric Company VVER-440 fuel was loaded into Fortum’s Loviisa NPP during the outage. About a quarter of the fuel in both reactors was replaced.
